Phineas and FerbOne Wild Weekend
by warpbait2
Summary: When Phineas and Ferb's family is away for a convention. Vanessa is stuck sitting them so she can earn some money to see a movie. after seeing a commercial for the same movie they develop a device to accelerate their age so they can get into the R rated film. However Dr. Doof's new invention changes there plans. My first story, will contain lemons later on, please read and review.
1. I know what we are going to do today

Disclaimer I Do not Own Phineas and Ferb or any of the characters in this story all I came up was the idea for this story. They belong to disney

Chapter 1

It was a normal day at the Flynn-Fletcher house with Candace shouting as usual. "Mom, Mom, the boys built a full scale replica of the Roman Coliseum in the backyard! Come quick before it disappears." Candace screamed. And as usual when Linda got to the backyard all she saw were Phineas and Ferb. "Hello boys, so where is the coliseum Candace?" asked Linda "I don't know, it was here a minute ago." Candace replied "Well maybe this weekend will be just what you need, a weekend without the boys, and your constant urge to "bust them". Linda, and Lawrence were leaving the next day to go to a antiquing convention for the weekend, and they were dragging Candace along with them so they could avoid constant phone calls, and to make sure there would not be another "intimate get-together". "But we might have to call it off if we can't find a sitter," said Linda with a sigh.

Meanwhile across town Vanessa Doofenshmirtz was asking her mother for some money to go see the horror film that had just came out Killer Cyborgs. "Come on mom, I need to see this movie" Vanessa begged. "I'm sorry Vanessa but my answer is no, if you want to see the movie so bad you could get a job, one of the women in my cooking class is looking for a sitter for the weekend." Her mother responded "and don't even think of giving me one of your, that is uncool excuses, either babysit or go without your movie." "Whatever, just give me their name." Said Vanessa "The Flynn-Fletchers" said Charlene "ask for Linda" Back at the Flynn-Fletcher house Linda received a phone call from Vanessa about the babysitting job. She told Vanessa to come over tomorrow morning around 10 so she could give her the emergency numbers, and answer any questions she might have.

The next morning at 10 Vanessa arrived at the house and was given the tour, kitchen, panic room and the master bedroom where she would be able to sleep for the weekend, she was also given Linda's number, 911, poison control, the usual emergency numbers. After the tour she saw the boys in the living room watching television where she immediately recognized Ferb. "Ferb? So this is your house then?" asked Vanessa. Ferb began to speak but was interrupted by Linda "Oh so you know each other, then this should be no problem for you." "Well we're off bye boys thanks again Vanessa. Oh and there is $100 dollars on the table for food and movies for the weekend" "Bye mom" the boys replied. After Linda, Candace, and Lawrence left Vanessa turned to the boys. "So what are you going to do today?" "We're not sure yet … hey where's Perry?"

On the other side of the house Perry the platypus was going into one of his secret tunnels, where on a large monitor was Major Monogram. "Good morning agent P, we have reports that Dr. Doofenshmirtz has been buying up all of the towns aphrodisiacs, we don't know what he's up to but go put a stop to it." Said MM, and with a salute Perry was off.

Back in the house a commercial came on for the new horror film Killer Cyborgs came on, and due to the sci-fi elements of the film, made Phineas and Ferb want to see it as well. However the movie was rated R, "Man Ferb too bad we are not 18, then we could go see the movie now … wait a minute, hey Ferb I know what we are going to do today."

Well that was the first chapter of my first story I will update again within the next day or so please review.


	2. Doof's plot and P&F's invention

Disclaimer I Do not Own Phineas and Ferb or any of the characters in this story all I came up was the idea for this story. They belong to disney

Chapter 2

At Doofenshmirtz Evil Incorporated Agent P crashed through Heinz's door and right into a trap, a cage shaped like a pair of balls. "Ah Perry the platypus how "ballsy" of you to show up, get it because your trapped in a pair of balls ha ha ha!" badly joked Dr. Doofenshmirtz. Perry rolled his eyes, "Eh well anyway I suppose you noticed I have been purchasing much of the towns aphrodisiacs (chocolates, strawberries, wine, etc.) "Well you see Perry the platypus I have been watching a lot of pornographic content and I have realized that sex is very distracting so I invented this." He shouted as he pulled the tarp off of a large object in the middle of the room, revealing a large cannon like device with a pair of lips on the front and a chute on the back for ingredients. "I call it my Sexinator, one hit by its beam and the target will be overwhelmed by an uncontrollable lust for sex." Explained Dr. Doof, as Perry began looking around at the cage and realized that his tail was still free enough to undo the latch in the back of the cage. Dr. Doof continued "By shooting the mayor's office and the surrounding area, they will be so distracted having sex that I will be able to waltz right in and take over the tri-state area, and made it so it only affects people 18 or older so my daughter will not be affected if she is in the area. Bwhahahah"

Back at Phineas and Ferb's house Isabella was walking into the backyard, "hey Phineas, what cha doooin'?" She asked in her usual manner. "Hi Isabella, we are going to go see a R rated movie." Phineas replied "Um Phineas aren't we a little young to go to a R rated movie?" "Yes, Yes we are, that's why we made a device to make us older." Phineas explained as he showed her a device that looked like a ray gun with a meter on each side. "Oh ok cool then can I come too?" "Of course. We are just about to test it now" Phineas replied. Vanessa walked out into the yard overhearing the conversation. "Make you older? How? " She asked. "Well first you turn the dial on the left to the age you want, I will put it at 18," He turned the dial on the left "then you set the amount of time on the right," He set the right dial to 3 minutes, "then you shoot." He shot Ferb with the beam, Ferb shot upward until he was about 6'2, and his face began to look more masculine. He grew light sideburns and his chest was now rippled with muscles, his shirt and pants grew enough to keep him covered but just barely concealing his now adult manhood. Vanessa's jaw dropped not only had she not expected the device to work but she definitely had not expected Ferb to turn out so good looking as an adult. Ferb began speaking in a much deeper voice then he used to, explaining how it worked, but Vanessa was distracted both by his new body and what she could make out in his pants. "… and that is how it worked" is all she caught. Then exactly 3 minutes after he was shot with the beam Ferb turned back to normal. "The timer is a failsafe so we can still turn back if our invention disappears like it usually does" said Ferb intelligently. "So with this we can all go see the movie?" Vanessa asked, "Yeah that's the plan" said Phineas "Then what are we waiting for fire it up so we can go." "Sure." Phineas said as he set the dials to 8 hours at 18 years old.

Ok so there was chapter 2 tell me what you think Isabella and Phineas, (and to a lesser extent) Vanessa should look like, the transformations and probably the lemons will happen next chapter, but be warned this will be my first attempt so don't expect perfection, please read and review.


	3. Transformation and the sexinator

Disclaimer I Do not Own Phineas and Ferb or any of the characters in this story all I came up was the idea for this story. They belong to Disney

Also thanks to Catchprasesteale for the suggestion of character design. So for facial reference for Phineas Ferb and Isabella look up team improbable

Chapter 3

As Phineas prepared to fire the invention at everyone he remembered something. "Oh yeah also anything that happens to your body after it's been hit reverts when the beam wears off Like if you cut your finger, when you turn back it will be healed." "Alright" everyone else responded. Phineas took aim at Ferb and fired, he turned back into his adult form, only this time his cloths could not handle the stress and they tore to pieces. Ferb blushed and covered himself while Phineas tossed him some clothes. "It's a good thing we still had a couple adult sizes of the cloths we made earlier this summer" said Phineas. Next he aimed at Vanessa who grew a little taller and her breasts expanded slightly, her midriff was now slightly exposed and her hair had grown a little longer. "Ok Isabella are you ready?" he asked as he aimed the ray at her. "Yes Phineas, maybe I should check to see if there is a grow older patch in my fireside girl's handbook." She replied, and then the beam hit her. She sky rocketed until she was 5'10, her dress tore so it looked like she was wearing a short skirt and a belly shirt. Her hips then expanded and her chest burst forward until they were even bigger then Vanessa's DD cups and she had reached a perfect hourglass figure. Her facial features became more pronounced and her lips became fuller (more full?) and her hair reached the small of her back. Her shirt barley covered anything with the bottom half of her breasts being visible, and her skirt and underwear now rode up so high that anyone could make out the outline of her sex. She quickly covered herself when she realized this and embarrassed asked Phineas shyly "Um Phineas do you have any cloths I can where?" "Sorry Isabella I don't but I think so, you're too big to fit into any of Candace or my mom's outfits and I don't even think you could fit in Vanessa's. He shot Vanessa a look and she shook her head, but I think we still have a bit of fabric left over in our room, hey Ferb can you make some cloths for her real fast?" he asked and Ferb nodded his head and was back with a adult size duplicate of Isabella's normal cloths in less than 5 minutes. "Thanks Ferb" she said. Then Phineas tossed the ray to Ferb who then shot him with the beam. Phineas grew until he was 6'0 his chest now roared with muscles even slightly more than Ferb and his hair grew very slightly. His normal cloths now were like a boa constrictor on his body, his shirt actually tore a bit and his shorts were so small on him that they looked like booty shorts. "Ferb toss me my cloths please" he asked and Ferb threw his brother his outfit, and he began to change right there in the backyard while everybody looked away. As Phineas got changed Isabella could not help but look over in his direction. What she saw made her mouth water though she had no idea why. Between Phineas' legs was a monster sized dick that could have been bigger than Ferb's (although she really had not been paying attention to Ferb so she was just guessing) she quickly turned away but not before she felt her panties dampen, while she was embarrassed she decided to ignore it. "Alright let's go to the movies" said Phineas after he got changed. Little did they know, a beam was coming right at them.

At the same time that the kids had started aging themselves, across town at D.E.I. Perry the platypus had broken out of his cage, and quickly delivered a roundhouse tail slap to Dr. Doofenshmirtz's face. "Perry the platypus, how did you get out?" "No matter your too late all I have to do is press this button and …" he said as he went to press the large red button. However right before he hit it Perry kicked the inator and made it spin out of control firing everywhere except at the mayor's office, before finally exploding. "Curse you Perry the Platypus!" Dr. Doofenshmirtz screamed as Perry flew off on his hang glider.

Back at Phineas and Ferb's house, Phineas, Ferb, Vanessa, and Isabella were getting ready to leave for the movie when one of the beams from the sexinator hit them causing the boys to get erections and the girls to get drenched. Vanessa could not control herself; she turned towards Ferb and pulled him in for a French kiss. Ferb was not sure why this was happening but he did not mind and he kissed Vanessa back whole heartedly as he felt her hand start moving toward his crotch. Isabella turned toward Phineas, kissed him on the lips and told him that she loved him, and then she let the lust take over. The next thing Phineas knew his best friend was taking off her dress to reveal all of her new assets and then getting on her knees pulling his pants down to his ankles. "Wow" is all she could say once she got his manhood out of his underwear, she had gotten a glimpse of it earlier but seeing all 10 inches in front of her face was a totally different sensation. She began licking the tip then slowly took the whole length into her mouth resulting in soft moans from Phineas. She began to pick up speed, bobbing her head back and forth faster and faster until she heard Phineas groan "Isabella I'm about to …" She quickly pulled him out of her mouth and wrapped her breasts around him and began to move them up and down his shaft licking the tip on every raise, until he finally let loose into her mouth where she drank every drop of the bitter liquid. "Wow Isabella where did you learn to do that?" He asked in awe "I don't know something just took over" she replied with a smile.

As Isabella was on her knees taking care of Phineas, Vanessa was doing the same thing for Ferb "Wow Ferb you are way bigger then Johnny" she exclaimed after seeing his 11' manhood, she expertly took him into her mouth and after doing some fancy work with her tongue had him finished in less than a minute. "Now it's on to the main course" she said as she got undressed, had him lay down and positioned herself above his pole. At the same time Isabella and Phineas were about to do the same thing only with Isabella on the ground. "Are you ready Isabella?" he asked "Yes I'm ready Phineas, now please fuck me" she replied. Phineas thrust himself into Isabella, slowly at first but quickly increasing speed causing her to moan "Yes OH PHINEAS!" "HARDER FASTER!" she screamed. Vanessa impaled herself on Ferb very quickly going up and down. "This is great, the best I have ever had." She said, then unexpectedly Ferb flipped her over and he began to thrust his hips quickly becoming in sync with her thrusts. All 4 of them quickly drew to their climax and managed to finish at the same exact time. Lying on the ground drenched in sweat Phineas looked over and saw his pet "Oh there you are Perry"

After 6 more hours of that (and lots of partner swapping and experimenting) the effects of both rays wore off. Isabella got dressed and went home talking about the possibility of sex patches. Then at the end of the weekend when the rest of the family arrived and paid Vanessa she turned to the boys and said "I think that you guys should keep that one somewhere safe, I might have to come by a bit more so we can do that again." She said, she waved goodbye and went back home having completely forgot the reason that she took the job in the first place.

Well that was my first story and my first lemon please review. Oh and also If you liked the idea of this story and want to do it yourself (for any reason) go for it you don't even have to credit me for the idea if you don't want to, just please tell me when your version is done so I can see for myself


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